An image-forming apparatus employing solid-ink pellets, such as a printer, a fax machine, or a photocopier, includes a system for extracting pellets from a container for delivery to the image-forming apparatus. Conventionally, the solid ink pellets are placed in a container, and a feeding mechanism extracts the pellets and transports them to a heater assembly. There, the heater melts the pellets and a feeding mechanism applies the resulting liquid to media to form images.
In general, solid-ink pellets are stored in a container, from which pellets are extracted for print production as required. Typically, an extraction tube is inserted into the container, suction is applied to the extraction tube, and the resulting airflow entrains the solid-ink pellets from an extraction inlet in the extraction tube.
A flow problem can arise, however, when pellets bridge or clump together. This process, known as agglomeration, can occur when the pellets are stored in the container, as adjacent particles tend to fuse together under the combined action of temperature and pressure. Also, static charges on individual particles can cause attraction between adjacent particles, leading to agglomerations. Further, the prilling process employed to manufacture the solid-ink pellets can result in the pellets being brought into close proximity before they have cooled, likewise leading to agglomerations. The resulting clumps or agglomerations may exceed the size of the extraction inlet, clogging the flow of the solid-ink pellets.
Known approaches to this problem aim to break up the bridges and clumps, employing a variety of mechanical means. Generally, these solutions adapt the extraction tube to provide a device that manually agitates the solid-ink pellets to break up the agglomerations. This manual agitation must be performed sufficiently often to maintain the desired flow of solid-ink pellets. Where a number of agglomerations have formed, significant operator intervention may be required. Moreover, the agitation process itself interrupts pellet movement, and it often fails to produce the pellet movement once clumps have clogged the system.
In general, containers store considerable volumes of solid-ink pellets, and manually agitating the container may be cumbersome. In another alternative solution, mixers or grinders are coupled to the container to break obstructions. Current solutions, however, limit the breakage of agglomerates to positions near the extraction tube, thereby reducing both the efficiency of the breakage mechanism as well as the flowability of the solid-ink pellets.
It would be highly desirable to have a simple and cost-effective system that identifies an appropriate time for agitating pellet agglomerations, and further maintains flowability of solid ink-pellets from a container, breaking up clumps and agglomerates.